Rotary coiled broom

ABSTRACT

A street sweeping broom which is comprised of a rotary helical brush strip tightly secured about a rigid cylindrical core. The brush strip is of generally conventional construction and includes a plurality of reversely bent bristles with the bights thereof being maintained within a channel member by an anchoring wire and by the crimping of the channel member at spaced locations along the length thereof. Each of the ends of the helical brush strip is secured to a guide member which also supports the coil directly adjacent to the end of the brush strip. A ring having a plurality of circumferentially spaced slots is secured to each end of the core, and the guide members are attached to the rings by means of an inclined, inwardly projecting tang which allows movement of the guide member in only one rotational direction upon the ring. Thus, ratchet-type mechanisms are provided to secure each end of the brush strip to the core which mechanisms act to automatically take up any slack in the brush strip during the usage thereof in order to maintain it in tight engagement with the core.

United States Patent 1 1 Rosseau 1 Aug. 26, 1975 [5 ROTARY COILED BROOM [75] Inventor: Richard B. Rosseau, Claremont,

Calif.

[73] Assignee: FMC Corporation, San Jose, Calif.

[22] Filed: July 23, 1974 [21] App]. No.: 491,021

Primary ExaminerPeter Feldman Allorney, Agent. or FirmR. S. Kelly; C. E. Tripp [57] ABSTRACT A street sweeping broom which is comprised of a rotary helical brush strip tightly secured about a rigid cylindrical core. The brush strip is of generally conventional construction and includes a plurality of reversely bent bristles with the bights thereof being maintained within a channel member by an anchoring wire and by the crimping of the channel member at spaced locations along the length thereof. Each of the ends of the helical brush strip is secured to a guide member which also supports the coil directly adjacent to the end of the brush strip. A ring having a plurality of circumferentially spaced slots is secured to each end of the core, and the guide members are attached to the rings by means of an inclined, inwardly projecting tang which allows movement of the guide member in only one rotational direction upon the ring. Thus, ratchet-type mechanisms are provided to secure each end of the brush strip to the core which mechanisms act to automatically take up any slack in the brush strip during the usage thereof in order to maintain it in tight engagement with the core.

21 Claims, 4 Drawing Figures ROTARY COILED BROOM particularly, it pertains to the means whereby a heli cally coiled brush strip can be maintained in a tight condition upon the cylindrical surface of a broom core member under full load conditions.

2. Description of the Prior Art A typical construction for a rotary power brush, such as might be used on street sweepers for example, comprises a generally cylindrical core member about which a helical brush strip is tightly wrapped. The brush strip includes a channel having a tightly bunched, continuous series of reversely bent bristles secured therein. The bristles are arranged to be secured within the chan nel at their bight portions by means of an anchoring wire or cable which extends the full length of the brush strip. In operations such as street sweeping where the bristles wear quite rapidly. the frequent changing of the brush strip becomes necessary, and it is highly desirable that this operation be capable of being performed in the field by relatively unskilled personnel and not require complex and costly winding and tightening equip ment such as would be found only at a brush making factory.

in one rotary brush construction of the aforedescribed type that is widely used in the street sweeper industry and is shown in prior US. Pat. No. 3,193,866 to Jones, one end of the brush strip is fastened to the core by means of a slack accumulator device which comprises a flexible cable attached to the end of the brush strip and to the end face of the core so as to allow the brush strip to rotate in one direction if slack develops along the length thereof but preventing it from rotating in the opposite direction wherein it would unwind from the core. When slack does develop in the brush strip, the attachment of the aforementioned cable to the end face of the core can be loosened, and the brush strip can be pulled tighter about the core to remove such slack before reclamping the cable to the core. Thus. by means of periodic manual take-up of the slack in the brush strip, the brush strip can be maintained in a fully tightened condition on the core so as to prevent damage to the strip such as mightoccur if the'end of the strip were permitted to move freely on the core and strike its retaining mechanism.

In the aforementioned prior art rotary coiled brush construction as shown in US. Pat. No. 3,193,866, it was found to be necessary to provide a fixed helical track upon the surface of the core for receiving the coiled brush strip in order to maintain the coils of the brush strip in the proper spaced relationship in order to achieve a good brushing action with the broom. If the track were not provided, any slackness which developed in the brush strip might result in a spreading of certain adjacent coils which would leave an undesirable streak in the brushed strip of road surface or pavement.

An attempt to improve this basic rotary coiled brush construction is disclosed in the recently issued US. Pat. No. 3,750,225 to Gould et a]. The rotary sweeping brush structure shown in this patent also includes a helical brush strip which is arranged to be rigidly secured about a cylindrical core element. However. no channel means are provided upon .the surface of the core element for holding the brush strip coils in place. Instead,

one or both ends of; the brush strip are provided with.

oneway clutch devices which provide for an automatic positive takeup of any slack in the brush strip as soon as it occurs. Thus, the need for the channel is allegedly obviated since the automatic take-up provided .by the brush strip mounting means will maintain the brush strip in, tight engagement with the core at all times.

The street sweeping brush disclosedin the aforemen tioned U.S. Pat. No. 3,750,225 has some disadvantages, however, which reduce its effectiveness. For example, as pointed out in the patent, the brush strip must be tightened by hand about the core element before it can be put into use upon a street sweepingve hicle. One

of the main reasons for this requirement of pre-* tightening is that the ends of the brush strip become unsupported after any slac'kness is takenup during the usage of the brush, and these free ends of the strip cannot be permitted to become too long. Slack accumulator devices are mounted upon the ends of the Gould et al core, and the ends of the brush strip are provided with extensionstgrooved or threaded in actual practice) which are adapted to move through such slack accumulator devices in one direction while being restrained from movement in the opposite direction. As the brush strip is tightened about the core the extension at the end thereof moves past the slack accumulator device and extends freely adjacent to the end of the core. If this free end becomes long enough, it can become entangled in the dirt shoes or side deflectors adjacent to the endof the core which could cause the brush strip to break unless a special guard plate is provided to prevent this from occurring. Also, there is a practical limit to the amount of take-up which can be provided by the device shown in the Gould et al patent because of the limited length of the brush strip extensions. Thus, initial tightening of the brush strip is required before the slack accumulator element is attached to the core so that the slack accumulator can be attached to the very end of the brush strip extension; Additional slack accumulation (under sweeper'load conditions) willbe limited to but a fraction of the circumferential length of one coil of the brush strip.

Another significant disadvantage of the street sweep ing brush disclosed in prior US. Pat. No. 3,750,225 is that no means are provided for aligningthe brush strip extension with the passage through the slack accumulator device. If the'brush strip extension is initially misaligned or becomesmisalignedcue to shifting of the end coil of the brush strip, the extensioncanbind in the slack accumulator device and the slack accumulator device will fail to function in its intended manner.

Another related disadvantage of the-street sweeping brush shown in the aforementioned prior US. Pat. No. 3,750,225 is that the self-tightening feature will not prevent the brush strip coils from'spreading at the ends of the core where it is particularly essential that the brush sweep cleanly. in order to prevent this problem. means must be provided (not shown in'the patent) for maintaining a fixed spacing of the end coils of the broom so that they will not shift axially on the core during the automatic tightening of the brush strip. This means (which takes the form of a clip removably secured to the core) also serves to align the last coil of the brush strip with the slack accumulator device so that the brush strip extension will feed freely therethrough without binding. This clip must be removed before the brush strip can be replaced on the core. and such removal has proven to be both a difficult and a disagreeable job.

Another solution to the problem of providing a continuous positive take-up means on the end of a helically coiled brush strip for maintaining the brush strip in tight engagement with a cylindrical core element is shown in U.S. Pat. No. 1,198,407 to Beckett. The brush strip shown in this patent is attached to the core element by means of a tension spring which may contract to take up slack developed in the brush strip during the usage of the brush. The spring in combination with the friction developed by the brush strip coils prevent rotary movement of the brush strip in the unwinding direction after the slack has been taken up.

SUMMARY OF THE INVENTION The apparatus of the present invention comprises a rotary sweeper broom structure which, like the broom structure shown in prior U.S. Pat. No. 3,750,225, is provided with means for allowing an automatic continuous take-up of the slack which inherently develops in brush strip coils that are helically wrapped upon an underlying, generally cylindrical core element. However, such continuous take-up of the slack is arranged to be truly unlimited, and, in fact, no hand tightening of any sort is required when the brush strip is initially placed on the core element prior to the use of the brush under load conditions, i.e., in a street sweeping situation. That is to say, the coiled brush strip can be merely slipped into place loosely over the core and attached loosely at its ends to the ends of the core, and then the assembled broom can be placed directly upon the powered street sweeper ready for use. Rotation of the brush in place and under load then provides the proper tightening of the brush strip coils. Like the brush of the aforementioned U.S. Pat. No. 3,750,225, no helical track means is generally required to keep the brush strip coils in the desired uniformly spaced relationship.

The brush strip is arranged to be held in place on the core by at least one ring member which is attached directly to the core at one end thereof. This ring member includes a series of spaced steps or recesses which extend circumferentially about the entire cylindrical surface of the ring member. A guide member is securely attached to the end of the brush strip adjacent to the ring member and is arranged to ride upon the surface of the ring member as the slack is removed from the brush strip. The guide member is provided with means that successively engages the spaced stops on the face of the ring member so as to permit relative rotational movement therebetween in one direction but preventing such relative rotational movement in the opposite direction. Thus, the end of the brush strip can rotate endlessly about the ring. and there is no practical or theoretical limit to the amount of slack take-up which can be obtained. In the preferred form of the invention the guide member is provided with means for slidably securing the brush strip coil at a position spaced one coil length from the end of the strip; this serves both to assure that the guide member will always be properly aligned with the ring member so that binding or jamming will not occur and to assure that the end coils of the brush strip will be properly positioned at the end of the core.

The present invention possesses several distinct advantages over the prior art rotary coiled brushes, particularly the device shown in the aforementioned prior U.S. Pat. No. 3,750,225. First, as mentioned hereinbefore, there is an unlimited amount of take-up which can be achieved, and this permits the brush to be installed with no pre-tightening of any kind being required. Also, in the preferred embodiment of the invention, the guide member is slidably attached to the brush strip one coil length from the end of the strip so that the end two coils of the brush strip are maintained in the proper closely spaced position close to the edge of the core where full and effective sweeping is essential. The guide member in the present invention will always be aligned with the ring member whereby binding or jamming will not take place so as to prevent the desired slack take-up movement from occurring. Another important advantage of the rotary brush structure of the present invention is that even after full slack take-up there is no free unsuported end of the brush strip which might become entangled in the dirt shoes or other mechanisms at the sides of the rotary broom structure.

The novel slack accumulating device of the present invention thereby comprises the aforementioned ring member and guide member, and such slack accumulating device may be provided at each end of the core if the brush strip is subject to loading in either rotary direction. Also, although it is preferred to attach the ring member to the core and the guide member to the end of the brush strip, it is possible to reverse this arrangement, i.e., attach the ring member to the end of the brush strip and the guide member to the end of the core, and still obtain the major advantages of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is an isometric view of one end of a rotary coiled broom which embodies the present invention with the coils of the brush strip thereof being broken apart and separated from the core for the purposes of illustration.

FIG. 2 is a fragmentary longitudinal section of the end 'of the rotary coiled broom shown in FIG. 1.

FIG. 3 is a reduced section taken along the line 3-3 of FIG. 2 with the brush strip being removed from the guide member to which it is attached for the purpose of clarity.

FIG. 4 is an enlarged section taken on the line 4-4 of FIG. 3 and illustrating the ratchet-type connection of the guide member with the underlying ring member.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring first to FIGS. I and 2, the rotary broom of the present invention will be seen to comprise a generally cylindrical core 10 about which is wrapped a helical brush strip 12, the brush strip extending the full length of the core in rather closely spaced coils (as is conventional). An axle I3 is arranged to support the core Upon a street sweeping machine (not shown) in the conventional manner. The brush strip, best shown in detail in FIG. 2, is entirely conventional in construction and comprises a coiled metallic supporting channel 14 within which is received a plurality of reversely bent and closely bunched bristles 16 that extend throughout the length of the brush strip. Each of the bristles is secured at the bight thereof within the supporting channel 14 by means of an anchoring wire 18 which. in the described embodiment of the invention. is a twisted pair anchoring wire as disclosed in prior US. Pat. No. 3,137,021. The bristles are additionally retained in the channel by intermittently spaced crimped portions 19 (FIG. 1) spaced along the outer side edges of the channel 14.

The improvement representing the present invention basically comprises the provision of means whereby at least one end of the brush strip 12 is secured to the end of the core I0 so that continuous positive accumulation of slack within the brush strip is obtained. For this purpose, a cylindrical ring member 24 is loosely assembled about the end surface of the core. This ring member comprises a relatively large cylindrical flange portion 26 and a relatively short cylindrical flange portion 27 which flange portions are separated by a radially outwardly extending track portion 28. The short flange portion 27 is positioned directly adjacent to the end of the core and is provided with a series of apertures 30 spaced about its circumference. Selected ones of the apertures 30 are arranged to receive cotter pins 32 (as shown in FIG. 1) in order to permit the attachment of the ring member to the core. The large flange portion 26 of the ring member includes a continuous series of uniformly spaced slots 34 which extend about the entire cylindrical surface of the ring member.

The end of the brush strip 12 is arranged to be securely attached to a clip or guide member that is arranged to ride upon the track portion 28 of the ring member 24 and is provided with means whereby it is permitted to move in only one rotary direction upon the surface of the ring member. This guide member, as best shown in FIGS. 2 and 3 of the drawings, comprises a clip which has a generally U-shaped body portion 42 arranged to receive the end of the brush strip. The side walls of the body portion 42 of the guide member are provided by a plurality of tabs 44 the upper ends of which are bent transversely (as shown in FIG. 1) into closely spaced adjacent relationship to securely lock the guide member about the channel 14 of the brush strip and within the radially extending bristles 16. A pair of reversely bent ears 46 extend laterally outwardly from the body portion 42 of the guide member and are adapted to be slidably received upon the track portion 28 of the ring member so that the guide member can freely slide about the circumference of the ring member. A pair of flanges 48 at the ends of the guide member extend laterally in the opposite direction from that of the ears 46 and, shown in FIG. 2 of the drawings. underlie and serve to slidably support the brush strip at a position spaced one coil length from the end of the strip. This arrangement serves to properly main tain the end coils of the brush strip close to the end of the core where they are needed. It should he noted that the end portions of flanges 48 are bent so as to extend radially outwardly and thus serve to maintain the coils of the brush strip on the guide member. It will also be recognized that the flanges 48 may extend along the core 10 for a distance sufficient to support several coils of the brush strip if it is desired to bunch the coils at the end of the core.

A particularly significant feature of the guide member 40 is that the body portion 42 thereof includes a radially inwardly struck tang 50 which extends rearwardly to the direction of travel of the guide member and at an inclined angle thereto. This tang is arranged to successively become engaged in the spaced slots 34 of the ring member as the guide member is slid about the circumference of the ring. The configuration of the tang is such that it will pass over the slots when the guide member and the brush strip held thereby are moved in one rotary direction (indicated by the arrow in FIG. 3 of the drawings) but it will prevent any movement of the guide member (and hence the brush strip) in the opposite direction due to the engagement of its flat radially extending face 50a with the trailing side edge of a slot the trailing side edges of the slots thereby serving as stops for the guide member. This locking engagement of the tang with the ring member is specifically shown in FIG. 4 of the drawings.

In order to further insure that the end coil of the brush strip will be maintained in the proper relationship with respect to the adjacent end of the supporting core, a second guide member or clip (FIGS. 1 and 2) is secured to the brush strip at a position spaced or one-half a coil length, from the end of the strip. This second clip 60 comprises a generally U-shaped member one side wall of which is formed by a tab 62 that is bent transversely at the upper edge so as to overlie the channel 14 of the brush strip and lock the brush strip thereto. The guide member 60 also includes a pair of laterally extending reversely bent ears 64 adjacent to the tab 62 for permitting the guide member 60 to ride upon the track portion 28 of the ring member in the same manner as that of the first guide member 40. It will be recognized that if the guide member 40 is provided with flanges 48 which are lengthened so as to support several coils of the brush strip, then the second clip 60 must be widened accordingly.

The aforedescribed means for securing a brush strip about a core ofa rotary sweeper broom may be utilized on virtually any conventional coiled brush strip-core construction. The guide member 40 is attached to the end coils of'the brush strip as shown and is merely placed upon the radially extending track portion 28 of the ring member. The operator who is to do the actual changing of thebrush strip will therefore be provided with a replacement brush strip which has attached thereto (on at least one end thereof) a guide member and a ring member in assembled relationship. To mount the brush strip upon the core it is then necessary to merely attach the ring member 24 to the end of the core with the cotter pins 32 as shown. As the brush strip tightens upon the core when the brush is subjected to loading (i.e., brushing) forces, the pull on that portion of the brush strip which is engaged by the supporting flanges 48 of'the guide member will force the guide member downwardly upon the ring member. Thus, the end of the brush strip which overlies the projecting tang 50 will always be in secure engagement with the ring member, and the guide member will always be aligned properly with the ring member to prevent binding therebetween. When it is desired to remove the brush strip for replacement, the ring member is merely removed from the end of the core by loosening the cotter pins 32, and a similar attachment means or fixed eon nection at the other end of the core is also removed. Then, the brush strip is allowed to unwind slightly so that it becomes loose enough on the core so as to permit the entire brush strip assembly to be slid axially from the core.

While the disclosed embodiment of the invention shows only one end of the brush strip as being attached to the core with the slack take-up means of the present invention. it will be understood that both ends of the brush strip can be attached with a similar device. and such method of attachment would be preferable, if not necessary, where the brush strip ,is subjected to brushing in either rotational direction during the usage thereof.

As pointed out hereinbefore, the brush strip may be tightened on the core merely by applying a sweeping load to the bristles of the brush strip. However, a preferred way of tightening the brush strip upon the core when the rotary broom is to be used in a powered street sweeper is to mount the assembled core and brush strip on the street sweeper machinery with the brush strip being in the aforementioned loosened condition upon the core. The coils can then be spaced by hand in the desired arrangement on the core as they will be free to slide axially on the core at this time. The broom-core is next accelerated rapidly while it is elevated above the ground surface. The quite large resulting inertia forces on the brush strip cause the guide member 40 at the end thereof to travel about the ring member 24 to fully take-up slack in the brush strip and cinch the brush strip down tightly upon the surface of the core. lfa similar slack accumulator structure is provided at the other end of the core. the foregoing procedure can then be repeated with the brush being driven in the reverse direction.

From the foregoing description it will be recognized that the rotary coiled broom assembly of the present invention provides a means whereby a conventional helically coiled brush strip can be tightened in place upon the conventional supporting core element. Since the slack adjustment mechanism of the present invention provides an endless amount of adjustment and does not leave a freely extending end or projection of the brush strip, there is no requirement whatsoever for initial hand tightening of the brush strip upon the core during the broom assembly. Thus. the operator need do no more than merely slide the brush strip upon the core, attach some cotter pins or the like, and then mount the assembly upon street sweeping equipment with the coils in the proper spacing and such street sweeping equipment will then be ready to operate. The take'up device of the present invention also eliminates the necessity for providing a helical track or similar fixed spacing means upon the surface of the core.

Although the best mode contemplated for carrying out the present invention has been herein shown and described. it will be apparent that modification and variation may be made without departing from what is regarded to be the subject matter of the invention.

I claim:

1. A rotary broom comprising a generally cylindrical core, a helical brush strip wound about said core, a ring member secured to one end of said core, said ring member having a series of stops spaced circumferen tially thereabout, and automatic tightening means provided at the cnd of said brush strip adjacent to said ring member for engagement with said stops on said ring member, said tightening means and said stops being configured and oriented so as to permit endless rclativc rotary movement therebetwcen in one direction and to prevent relative rotary movement in the opposite dircc tion when said tightening means is in engagement with one of said stops.

2. A rotary broom according to claim 1 wherein each end of said broom is provided with one of said ring members and wherein each end of said brush strip is provided with said automatic tightening means.

5 3. A rotary broom according claim 1 wherein said automatic tightening means comprises a guide member secured to said brush strip and having a projecting tang arranged to engage said stops on the associated ring member.

4. A rotary broom according to claim 3 wherein said ring member is provided with a track extending circumferentially about the periphery of said ring member and said guide member is provided with means for riding upon said track of the ring member.

5. A rotary broom according to claim 1 wherein said tightening means includes means for slidably supporting said brush strip at a position spaced one coil from said end of the strip in order to maintain said tightening means in engagement with said ring member and at least one coil of such brush strip at said end of said core.

6. A rotary broom according to claim 4 including a second guide member secured to said brush strip at a position spaced approximately one half coil from said end of the strip, said second guide member being arranged to be received upon said track of said ring member.

7. A rotary broom comprising a generally cylindrical core; a helical brush strip wound about said core; and automatic take-up means for maintaining said brush strip in tight engagement with said core including a ring member secured to one end of said core, said ring member having a series of recesses spaced circumferentially thereabout, and a guide member clamped to the end of said brush strip adjacent to said ring memher, said guide member having a projecting tang and being arranged to slide upon said ring member with said tang being received in said recesses, the interengagement of said tang and said recesses permitting said guide member to rotate about said ring member in one direction but preventing relative rotational movement therebetween in the opposite direction whereby any slack which accumulates in said brush strip will be removed by said automatic take-up means.

8. A rotary broom according to claim 7 wherein said ring member is provided with a radially outwardly extending flange, said guide member having a recessed portion arranged to be received upon said flange of the ring member.

9. A rotary broom according to claim 7 wherein said guide member is provided with means for slidably supporting said brush strip at a position spaced one coil from said end of the strip in order to maintain said guide member in slidable engagement with said ring member and at least one complete coil of said brush strip atsaid end of said core.

10. A rotary broom according to claim 7 including a second guide member secured to said brush strip at a position spaced approximately one half coil from said end of the strip, said second guide member being arranged to slidably engage said ring member.

1 l. A rotary broom according to claim 7 wherein said guide member comprises a generally Ushapcd member with the. arms thereof extending radially outwardly therefrom to receive said end of the brush strip and bent being bent over said brush strip to securely clamp the strip to the guide member. said tang projecting from the undersurface of said guide member, said guide member further including a laterally projecting ear arranged for sliding engagement with said ring member.

12. A helical brush strip for attachment to a generally cylindrical core of a rotary sweeper, said brush strip having a guide member securely attached to one end thereof, a ring member slidably attached to said guide member, said ring member being provided with a series of uniformly spaced stops extending circumferentially thereabout. means for securing said ring member to one end of said core, said guide member including means arranged to engage said stops on said ring member so as to permit endless relative movement of said guide member upon said ring member in one rotary direction but preventing relative movement therebetween in the opposite rotary direction.

13. A helical brush strip according to claim 12 wherein each end thereof has attached thereto one of said guide members and one of said ring members.

14. A helical brush strip according to claim 12 wherein said guide member is provided with a laterally projecting arm slidably engaged with said brush strip at a position spaced one coil from said end of the strip.

15. A helical brush strip according to claim 14 including a second guide member secured to said strip at a position spaced approximately one half coil from said end of the strip, said second guide member having means for slidably engaging said ring member.

16. In a rotary broom which includes a generally cylindrical core, a helical brush strip wound about said core, means securing each end of said brush strip to one of the ends of said core, and automatic take-up means provided at at least one end of said core for permitting take-up of any slack which accumulates in said brush strip so that said brush strip will be maintained in tight engagement with said core, the improvement wherein said automatic take-up means comprises a ring member attached to said core at said one end thereof, said ring member being provided with a series of stops extending cireumferentially thereabout, and a guide member secured to one end of the brush strip for riding engagement with said ring member, said guide member including means arranged to engage said stops on said ring member so as to permit endless relative movement of said guide member upon said ring member in one rotary direction but preventing relative rotary movement thercbetween in the opposite rotary direction.

17. In a rotary broom according to claim 16 wherein each end of said core is provided with said automatic takeup means.

18. In a rotary broom according to claim 16 wherein said guide member is provided with a laterally extending arm slidably engaged with and underlying said brush strip at a position spaced one coil from said end of the strip.

19. A rotary broom comprising a generally cylindrical core, a helical brush strip Wound about said core, a ring member at one end of said core, said ring member having a series of stops spaced circumferentially thereabout, means for securing said ring member to one of said core or said brush strip at the end thereof, and automatic tightening means secured to the other of said core or said brush strip for engagement with said stops on said ring member, said stops and said tightening means being configured and oriented so as to permit endless relative rotary movement therebetween in one direction and to prevent relative rotary movement in the opposite direction when said tightening means is in engagement with one of said stops.

20. A slack take-up device for maintaining a helically coiled brush strip in tight engagement with a generally cylindrical core, said take-up device being mounted at one end of said core and said brush strip, said take-up device comprising means for receiving and clamping the end of said brush strip. and guide means extending laterally from said last named means for slidably receiving said brush strip at a position spaced one coil length from said end of the strip whereby the end coil of said brush strip will always be maintained in a fixed position with respect to said end of said core.

21. A slack take-up device according to claim 20 wherein said guide means comprises a flange which is arranged to underlie said brush strip. 

1. A rotary broom comprising a generally cylindrical core, a helical brush strip wound about said core, a ring member secured to one end of said core, said ring member having a series of stops spaced circumferentially thereabout, and automatic tightening means provided at the end of said brush strip adjacent to said ring member for engagement with said stops on said ring member, said tightening means and said stops being configured and oriented so as to permit endless relative rotary movement therebetween in one direction and to prevent relative rotary movement in the opposite direction when said tightening means is in engagement with one of said stops.
 2. A rotary broom according to claim 1 wherein each end of said broom is provided with one of said ring members and wherein each end of said brush strip is provided with said automatic tightening means.
 3. A rotary broom according claim 1 wherein said automatic tightening means comprises a guide member secured to said brush strip and having a projecting tang arranged to engage said stops on the associated ring member.
 4. A rotary broom according to claim 3 wherein said ring member is provided with a track extending circumferentially about the periphery of said ring member and said guide member is provided with means for riding upon said track of the ring member.
 5. A rotary broom according to claim 1 wherein said tightening means includes means for slidably supporting said brush strip at a position spaced one coil from said end of the strip in order to maintain said tightening means in engagement with said ring member and at least one coil of such brush strip at said end of said core.
 6. A rotary broom according to claim 4 including a second guide member secured to said brush strip at a position spaced approximately one half coil from said end of the strip, said second guide member being arranged to be received upon said track of said ring member.
 7. A rotary broom comprising a generally cylindrical core; a helical brush strip wound about said core; and automatic take-up means for maintaining said brush strip in tight engagement with said core including a ring member secured to one end of said core, said ring member having a series of recesses spaced circumferentially thereabout, and a guide member clamped to the end of said brush strip adjacent to said ring member, said guide member having a projecting tang and being arranged to slide upon said ring member with said tang being received in said recesses, the interengagement of said tang and said recesses permitting said guide member to rotate about said ring member in one direction but preventing relative rotational movement therebetween in the oppositE direction whereby any slack which accumulates in said brush strip will be removed by said automatic take-up means.
 8. A rotary broom according to claim 7 wherein said ring member is provided with a radially outwardly extending flange, said guide member having a recessed portion arranged to be received upon said flange of the ring member.
 9. A rotary broom according to claim 7 wherein said guide member is provided with means for slidably supporting said brush strip at a position spaced one coil from said end of the strip in order to maintain said guide member in slidable engagement with said ring member and at least one complete coil of said brush strip at said end of said core.
 10. A rotary broom according to claim 7 including a second guide member secured to said brush strip at a position spaced approximately one half coil from said end of the strip, said second guide member being arranged to slidably engage said ring member.
 11. A rotary broom according to claim 7 wherein said guide member comprises a generally U-shaped member with the arms thereof extending radially outwardly therefrom to receive said end of the brush strip and bent being bent over said brush strip to securely clamp the strip to the guide member, said tang projecting from the undersurface of said guide member, said guide member further including a laterally projecting ear arranged for sliding engagement with said ring member.
 12. A helical brush strip for attachment to a generally cylindrical core of a rotary sweeper, said brush strip having a guide member securely attached to one end thereof, a ring member slidably attached to said guide member, said ring member being provided with a series of uniformly spaced stops extending circumferentially thereabout, means for securing said ring member to one end of said core, said guide member including means arranged to engage said stops on said ring member so as to permit endless relative movement of said guide member upon said ring member in one rotary direction but preventing relative movement therebetween in the opposite rotary direction.
 13. A helical brush strip according to claim 12 wherein each end thereof has attached thereto one of said guide members and one of said ring members.
 14. A helical brush strip according to claim 12 wherein said guide member is provided with a laterally projecting arm slidably engaged with said brush strip at a position spaced one coil from said end of the strip.
 15. A helical brush strip according to claim 14 including a second guide member secured to said strip at a position spaced approximately one half coil from said end of the strip, said second guide member having means for slidably engaging said ring member.
 16. In a rotary broom which includes a generally cylindrical core, a helical brush strip wound about said core, means securing each end of said brush strip to one of the ends of said core, and automatic take-up means provided at at least one end of said core for permitting take-up of any slack which accumulates in said brush strip so that said brush strip will be maintained in tight engagement with said core, the improvement wherein said automatic take-up means comprises a ring member attached to said core at said one end thereof, said ring member being provided with a series of stops extending circumferentially thereabout, and a guide member secured to one end of the brush strip for riding engagement with said ring member, said guide member including means arranged to engage said stops on said ring member so as to permit endless relative movement of said guide member upon said ring member in one rotary direction but preventing relative rotary movement therebetween in the opposite rotary direction.
 17. In a rotary broom according to claim 16 wherein each end of said core is provided with said automatic take-up means.
 18. In a rotary broom according to claim 16 wherein said guide member is provided with a laterally extending arm slidably engaged with and underlying said brush striP at a position spaced one coil from said end of the strip.
 19. A rotary broom comprising a generally cylindrical core, a helical brush strip wound about said core, a ring member at one end of said core, said ring member having a series of stops spaced circumferentially thereabout, means for securing said ring member to one of said core or said brush strip at the end thereof, and automatic tightening means secured to the other of said core or said brush strip for engagement with said stops on said ring member, said stops and said tightening means being configured and oriented so as to permit endless relative rotary movement therebetween in one direction and to prevent relative rotary movement in the opposite direction when said tightening means is in engagement with one of said stops.
 20. A slack take-up device for maintaining a helically coiled brush strip in tight engagement with a generally cylindrical core, said take-up device being mounted at one end of said core and said brush strip, said take-up device comprising means for receiving and clamping the end of said brush strip, and guide means extending laterally from said last named means for slidably receiving said brush strip at a position spaced one coil length from said end of the strip whereby the end coil of said brush strip will always be maintained in a fixed position with respect to said end of said core.
 21. A slack take-up device according to claim 20 wherein said guide means comprises a flange which is arranged to underlie said brush strip. 